2001 Jimmy shifts into 4wd on freeway on its own.

[mark44004]

Got a 2001 jimmy. When I'm traveling down the freeway at speeds of 60 mph or more, the suv shifts from 2wd into 4 wheel drive on its own. I have to stop and you can tell its in 4wd as it makes the whirring noise as i go to stop. Servo, actuator, ? any helps? Thanks.

[FishFind]

Change the selector switch first. Most of the time it is the problem. After that from what I have heard its the TCCM. Do the switch first though. They are like $30 and most of the time this is the fix.

[maxwedge]

Originally Posted by FishFind

Change the selector switch first. Most of the time it is the problem. After that from what I have heard its the TCCM. Do the switch first though. They are like $30 and most of the time this is the fix.

Agreed, they were troublesome on all the GM trucks including mine.

[gmtech1]

Also, look at the conectors to the TCCM, they are prone to get water in them and the terminals get corroded. If you see green fuzzys, that is not good.

[snorander]

I had this problem for a long time in my 2001 jimmy. It would shift in & out of 4wd hi on it own all the time. I replaced the selector switch, the TCCM and it did not go away. It turns out the vacum switch on my transfer case was bad an let fluid into the vacum lines. Crawl under your truck unplug the vacumn line from the top of the transfer case and see if any fluid drips out. If it does you need to let the lines drain and replace the vacum switch. It worked for me & I have had zero problems since. It is a lot cheaper to replace the vacum switch